1. Field of Invention
This invention relates to dielectric compositions, and more particularly to Barium-Strontium-Titanium-Silicon-Tungstate based dielectric compositions that exhibit a dielectric constant K=200-500 and that can be used in low temperature co-fired ceramic (LTCC) applications with noble metal metallizations.
2. Description of Related Art
The state of the art materials used in LTCC systems for wireless applications use dielectrics with dielectric constant K=4-8 and with Q factors around 400-1,000 at the measuring frequency of 1 MHz. This is generally achieved by using a ceramic powder mixed with a high concentration of a BaO—CaO—B2O3 low softening temperature glass which allows the low temperature densification (900° C. or lower) of the ceramic. This large volume of glass can have the undesirable effect of lowering the K and Q values of said ceramic. Q factor=1/Df, where Df is the dielectric loss tangent. There is growing demand for dielectric materials with higher K values larger than 10 for electromagnetic interference filter and band pass filter applications. However, it is more challenging to sinter higher K dielectrics at temperatures below 900° C.